1. Field of the Invention
The invention relates to an electric connector including a housing, and an electric terminal projecting through a bottom of the housing into the housing and sealed therearound with light-curing resin.
2. Description of the Related Art
In an electric connector used outdoors or used in a receptacle filled with fluid, holes through which electric terminals are inserted are sealed with resin to thereby close gaps in order to prevent penetration of fluid and/or dust. Such electric connectors have been suggested, for instance, in Japanese Patent Application Publications Nos. H10(1998)-284170, 2009-181798 and 2010-267512.
Japanese Patent Application Publication No. H10(1998)-284170 has suggested a connector including a housing in which connection terminals are housed, and a cover which is able to open and close relative to the housing. Between the housing and cover is filled with ultraviolet-curing resin in the form of gel to thereby make gaps formed among an area in which the connection terminals and electric wires are fixedly connected with each other, the housing, and the cover fluid-tight.
Japanese Patent Application Publication No. 2009-181798 has suggested a connector including a housing having a sealant layer and a height judge in order to hermetically seal a plurality of holes through which contacts are inserted, formed through a bottom of the housing. The sealant layer is composed of a ultraviolet-curing resin, a resin curing at a room temperature, or a resin curing when heated. The height judge is formed at a bottom of the housing for determining an optimal height by which the sealant is filled.
Japanese Patent Application Publication No. 2010-267512 has suggested an optic and electric connector including a receptacle connector, and a plug housing into which the receptacle connector is fit. The plug housing is formed with a first recess in which a photoelectric transfer part which converts optic signals into electric signals and vice versa, and optical parts for transferring optic signals are arranged, and a second recess in which an electric part which processes only electric signals is arranged. After the first recess was sealed with ultraviolet-curing resin, the second recess is sealed with a resin curing when heated.
Hereinbelow is explained a conventional electric connector with reference to FIGS. 1 and 2.
As illustrated in FIGS. 1 and 2, a conventional electric connector 100 includes a box-shaped housing 110 having an opening, and a plurality of electric terminals 120 inserted into a bottom 111 of the housing 110 and projecting into the housing 110 at distal ends 121 thereof. A sealant layer 130 composed of light-curing resin is formed at the bottom 111 of the housing 110 for hermetically sealing the electric terminals 120. Gaps formed between the electric terminals 120 and holes 112 of the housing 110 through which the electric terminals 120 are inserted are filled with the sealant layer 130 for sealing therebetween. While the electric connector 100 is being transferred on a conveyer, light-curing resin is supplied by a dispenser into an inner space 113 of the housing 110, and then, a light is vertically irradiated onto the light-curing resin for curing the same.
However, the conventional electric connector 100 illustrated in FIGS. 1 and 2 is accompanied with a problem that the sealant layer 130 may be peeled off a peripheral edge of the housing 110 at the bottom 111 thereof.
Since a peripheral edge 114 of the bottom 111 of the housing 110 is defined with a flat bottom 115, and an inner wall 116 standing vertically relative to the bottom 115, a portion of the inner space 113 in which the sealant layer 130 is formed has a constant depth. Since the portion of the inner space 113 has a constant depth, and further since light-curing resin is cured in accordance with a total amount of curing-lights irradiated by a curing-light lamp, a period of time necessary for curing the sealant layer 130 in a peripheral area 131 by means of vertically irradiated curing-lights is equal to a period of time necessary for curing the sealant layer 130 in a central area 132.
If a period of time for irradiating a curing-light to the sealant layer 130 were not sufficient for the sealant layer 130 to be cured, the sealant layer 130 could not be sufficiently cured with the result of reduction in an adhesive force between the sealant layer 130 and the housing 110. In such a case, since the sealant layer 130 broadly makes close contact with the bottom 115 in the central area 132, the sealant layer 130 can have a sufficient adhesive force, however, since the sealant layer 130 makes contact with the bottom 115 only in a small area in the peripheral area 131 of the sealant layer 130, the sealant layer 130 may be peeled off a periphery of the bottom 111 of the housing 110 due to radical oscillation and/or temperature fluctuations. If the peeling of the sealant layer 130 from a periphery of the bottom progresses to an area around the electric terminals 120, it is afraid that fluid may penetrate the sealant layer 130. In such a case, it is necessary to reduce a speed at which a conveyer transfers the electric connector 100 with the result of deterioration of a yield, unless it takes a sufficient period of time for curing light-curing resin.
That is, if light-curing resin of which the sealant layer 130 is composed could be cured in a short period of time, it would be possible to accomplish a high yield, and if the sealant layer 130 could be prevented from peeling off the housing 110, it would be possible to have high reliability.